Self-cooling roof structure



Oct. 31, 1961 J. F. BARNES ETAL SELF-COOLING ROOF STRUCTURE Filed Feb. 12. 195"! /1 1 g AZ INVENTURS ATTORNEYS.

United States Patent 3,006,113 SELF-COOLING ROOF STRUCTURE James F. Barnes, Van Nuys, and Herman I. Silversher, Tujunga, Califi, assignors to Foil Process Corporation, Van Nuys, Califi, a corporation of California Filed Feb. 12, 1957, Ser. No. 639,778 2 Claims. (Cl. 50-64) This invention relates to a self-cooling roof structure. Such would have particular application in those areas where there is a prolonged Warm season.

A cool roof is considered desirable for comfortable living in warm climates. To a certain extent this can be achieved by constructing the roof of a reflective material- Despite such a construction, there is still heat transfer inwardly through the roof to raise the internal temperature of the building.

It is a general object of our invention to provide a selfcooling roof structure. Another object is to provide a self-cooling roof structure wherein the amount of heat transferred into the building is reduced. Still another object of our invention is to provide self-cooling roof panels that can be readily assembled and installed. Still another object of our invention is to provide a self-cooling roof panel Where the outer surface is a reflector. Still another object is to provide a self-cooling roof element where air passage means are provided for convection cooling of the interior of the roof structure. Still another object is to provide a self-cooling roof element made up of a foil laminate. Still another object is to provide a selfcooling roof element constructed of sheets of metal foil bonded together by a thermo-insulating adhesive. Other objects and advantages of our invention will be seen as this specification proceeds.

In one embodiment of our invention we provide a laminated assembly of superimposed metal foil layers secured together by intervening layers of a metal-bonding adhesive. One of the adhesive layers is interrupted along spaced parallel lines to provide an air passage between adjacent layers of metail foil.

Various types of metal foil can be employed such as aluminum, copper, stainless steel. We have had excellent results using aluminum foil. For the metal-bonding adhesive we prefer to use an adhesive that possesses substantial resistance to heat transfer, especially in comparison to the metal foil employed in the laminate.

Our invention will be explained in conjunction with the accompanying drawing in which- FIGURE 1 is a top view of the self-cooling roof structure of our invention; FIG. 2 is a cross-sectional view taken along the line 22 of FIG. 1; and FIG. 3 is a fragmentary cross-sectional view of a building provided with a roof equipped with the self-cooling roof structure of our invention.

Referring now to the drawing, and particularly FIG. 2, the self-cooling roof structure of our invention is generally designated and is seen to include a number of layers of foil 11 bonded together by intervening layers of adhesive 12. As can be seen from FIG. 2, the adhesive layers 12 have thicknesses of about the order of the thicknesses of the sheets or foils 11.

One of the intermediate layers of adhesive 12, designated 12a, is interrupted along spaced parallel lines 13. The foil sheets on one side of the interrupted layer are seen to be flat while those on the other side of the interrupted adhesive layer 12a are seen to be arcuately deformed into an outwardly convex shape between the spaced parallel lines designated 13 in FIG. 2.

The general make-up of a roof provided with the laminate constructed according to the segment shown in FIG. 2 can be appreciated from a consideration of FIGS. 1 and 3 of the drawing. FIG. 1 is a top or plan view and shows a number of parallel spaced ridges 14 corresponding to the outwardly convex portion of FIG. 2. FIG. 3, in effect, shows a side view of the self-cooling roof structure. In FIG. 3, a building such as a house or the i like is-providedwith an inclined roof. The roof, which is generally designated 15, is made up of truss members 16 overlaid with board members 17. Overlaying board members 17 is tar paper sheeting 18 which in turn is covered by a layer of asphalt 19. In FIG. 3, the two sides of the roof are secured together along the center line of the building over which a ridge pole 20 is provided.

In FIG. 3 a number of elements or panels, as shown in FIG. 1, are arranged in side-by-side relation, designated 10a, 10b and 100. Arrows are shown on FIG. 3 indicating the flow of air through the passage 21 of FIG. 2 provided by outwardly convex portion 14 and the flat portion of our roof element 10, the flat portion being designated 14a.

We prefer to provide the passage providing upper layers of laminate in a form somewhat shorter than the lower layers 14a. The overlap of the flat layer is designated 22 in FIG. 1. By abutting elements 10 along their edges having overlapping portions 22, it is possible to provide 'air passages of shorter length than the inclined dimension of the roof. Alternatively, it is possible to off-set the arcuate portions 14 of one structural element with respect to another and achieve the same result without the need of resorting to overlap 22. Where adjacent ele ments abut, we provide flashing 23.

Referring again to FIG. 2, it is to be noted that in the pictured embodiment we provide the extreme outer layer of the laminate designated 24 as metal foil. If the foil provided is aluminum, good reflectivity can be achieved. It is also to be noted that the upper layer of the laminate serving to define passage 21, is also of aluminum. This upper layer is designated 25 in FIG. 2. In our preferred construction, the outermost layer of the lower portion 14a of the laminate is also provided of metal foil.

The laminate structure here described results in a superior self-cooling roof since all heat attempting to pass through the laminate tends to concentrate about the air passage 21 and therefore can be removed readily by convection currents. In operation, the outer layer 14, being a good reflector, reflects a substantial portion of the suns rays, and therefore contributes to maintaining the roof cool. Any heat that penetrates outer layer 14 tends to become concentrated in the inner-upper foil layer 25. Heat reaching the inner surface of the adhesive layer between foil layers 14 and 25 will be readily transmitted to foil layer 25 because of its greater thermal conductivity. Once the heat reaches foil layer 25 it is immediately available for transfer to convection currents passing through passage 21. Heat contacting layer 25 in the area between ridges 14 will preferentially be directed toward passage 21 since its further passage inward is opposed by a number of thicknesses of adhesive which are much less conductive to heat than the metal foil. The flow of air through passage 21 maintains the foil members defining the passage in'a cooled condition. This has a substantially similar effect on heat in the lower portion of the laminate.

Various adhesive materials can be employed while still achieving some of the advantages of this invention. Generally the adhesive should be selected for its capacity to form a strong bond with metals and particularly with aluminum. Suitable adhesives for some purposes include those falling within the classes of thermosetting resin adhesives, thermoplastic resin adhesives, and elastomeric adhesives. The thermosetting resin adhesives are preferred, and particularly the epoxy resin adhesives. These resin adhesives havesubstantial resistance to the transfer of heat, and are not subject to flow .even at substantially elevated temperatures. Epoxy resin adhesives upon first application and when only partially cured are flexible and resilient, while being curable by the application of heat to a condition of increased rigidity. Moreover, such adhesives function as good bonding agents whether or not they are completely cured to a rigid, infusible condition. A wide range of properties can be achieved with regard to the product either in its final condition or for intermediate processing operations. The epoxy resin adhesives can be applied in the form of liquids, solvent solutions, or for short periods of time as hot solutions (melts), or melted B-stage powders. When the adhesive is used in the form of a solvent solution, the components of the adhesive can be dissolved in the suitable solvent and the solution applied to the foil. If desired, the adhesive solution can be applied to one surface of a coil sheet and the solvent evaporated therefrom before the second sheet is applied. The advantages of using epoxy resins include excellent adhesion to clean metal surfaces without complicated surface preparations. The hardening (or polymerization) mechanism is one of addition rather than condensation. This means that no by-products are formed to interrupt the long chain formations. These can be manifested in the formation of a gaseous pocket. Pressure must be employed to prevent this in laminates using condensation polymerized products, while only a minimum or contact pressure is adequate to produce a good epoxy film. Another advantage of this mechanism is the low shrinkage factor that does not tend to distort the desired structural dimensions.

One particularly suitable adhesive consists of the reaction product of an epoxy resin and a polyamide. These components can be heated individually to a temperature of 90 to 100 C. to soften them, then mixed and applied. Reaction between the two components gives a cross-linked polymer having characteristics of hardness and flexibility in curing time which vary with the mixing proportions and temperature or curing. Usually about a 65-35 mixture of epoxy resin and polyamide gives good results. These components can be dissolved in methylethyl ketone or toluene, xylene, or comparable solvents for application as solvent solutions. Among the commercially available epoxy adhesives which may be mentioned are the Epon adhesives VI and VII of Shell Chemical and the Araldite adhesives ANll and AN-l04 of Ciba. However, the preferred adhesives for this invention are not limited to those prepared from the interaction of epoxy resins and polyamides. They may also be made by reacting epoxy resins with amine hardeners and cross-linking agents. These in the main are the polyamines of various molecular weights as ethylenediamine, phenylenediarnine, etc. Mixtures of polyamines and diamines can also be used.

A specific example of a thermosetting epoxy resin adhesive suitable for use in the present invention is formulated as follows: 60 parts by weight of Epon 1001 is dissolved in 30 parts of toluol and 30 parts of methylethyl ketone. A second mixture is formed from 32 parts of Polyamide 115, 11 parts toluol, and 3 parts butanol. 120 parts of the first mixture combined with 46 parts of the second mixture to form an epoxy resin adhesive solution contains 55.4% solids. This adhesive was used as is, but it can be thinned to, a different consistency with a mixture of parts toluol and 1 part butanol. If faster drying is desired, additional quantities of methylethyl ketone can be added. In the 55.4% solids concentrate the adhesive mixture has a pot-life in excess of 12 hours and this can be increased by adding additional quantities of solvents. Epon 1001 is an epoxy resin manufactured by Shell Chemical Company, which has an epoxide equivalent of 450 to 525. Polyamide 115 is a condensation product of dilinoleic acid and ethyldiamine produced by General Mills.

As a specific example of a phenolic thermosetting resin 4 adhesive which can be used in the practice of the present invention, the following is illustrative: parts of Plyophen 169 is combined with 100 parts by weight of a 10% solution of Butvar 3-76 in methylethyl ketone. Plyophen 169 is a phelofor-maldehyde resin manufactured by Reichhold Chemicals of White Plains, New Jersey. The product contains 64 to 68% solids, the resin being dissolved in methenyl. Butvar B76 is a polyvinyl butyrl resin in a 10% solid solution methylethyl ketone. It is manufactured by the Monsanto Chemical Company. If desired, Paracril CV can be substituted for Butvar B-76. Paracril CV is rubbery solid butadiene-acrylonitrile copolymer manufactured by the Naugatauk Chemical Company of Naugatauk, Connecticut. As modifiers for the phenolformaldehyde, soluble nylon or neoprene rubber can be used. Also, the Formvar resins can be substituted for all or part of the Butvar B-76. The Formvar resins are produced by the Shawinigan Chemical Company of Springfield, Massachusetts.

In manufacturing the self-cooling roof structure of the present invention, various procedures can be followed. In one procedure, fiat sheets would first be formed, then molded into desired shape by suitable deforming machinery such as press rolls. A multiple-head press roll can be employed to form the top portion of the laminate as shown in FIG. 1. 'In this process, the adhesive bonding layers would be in a flexible and deformable state and would not be completely cured. The sheet laminate would then be cut in lengths of the desired size, and mated with corresponding lower sections to provide a cross-section of the form shown in FIG. 2. The completed roof panel member would then be cured. For example, it could be cured for 10 minutes at 300 F.

This invention is further illustrated by the following specific examples.

Example I A roof panel of the structure shown in FIG. 1, having the cross-section represented by FIG. 2, is formed from four sheets of hard aluminum foil ranging from 3 to 5 mils in thickness. Two sheets of foil each are laminated together using a thermosetting epoxy resin adhesive, formulated as follows:

Ingredients: Parts by weight Epon 1001 30 Polyamide 11S l6 Methylethyl ketone 15 Toluol 20 Butanol 1.4

Example 11 A roof panel similar to that shown in FIGS. 1 and 2 can be produced according to the procedure of Example I but wherein the adhesive employed is about a 1.5 mil thickness of Bloomingdales which is manufactured by Bloomingdale Rubber Company of Chester, Pennsylvania. Another example is Plycozite of US. Plywood Corp., New York, New York. After curing, suflicient flexibility still remains in the roof panel to permit it being rolled to form a convenient shipping bundle.

The foregoing detailed description has been given for clearnesss of understanding only and no unnecessary limitations are to be inferred therefrom.

We claim:

1. In combination with an inclined roof, a plurality of roof panels covering said roof and providing a plurality of parallel, upwardly-inclined air passages, each of said panels comprising at least four superposed foil sheets constructed of a reflective metal, adjacent sheets being united by interposed layers of a metal-bonding adhesive, each adhesive layer being a thermal insulator and having a thickness of about the order of said sheets, an intermediate layer of adhesive being interrupted between a pair of spaced parallel lines, said intermediate layer being so positioned in said panel as to have at least two foil sheets on each side thereof, the foil sheets below said intermediate layer being flat with the outermost foil sheet thereof being adjacent said root, the foil sheets above said intermediate layer of adhesive being longitudinally convexly deformed between said spaced lines to provide an air passage, the other layers of said adhesive being continuous and generally coextensive with said sheets, said panels being arranged in side-by-side relation and the foil sheets above said intermediate layer being shorter than the sheets below said intermediate layer in the direction of said lines, whereby said air passages are shorter than the inclined dimension of said roof.

2. In combination with an inclined roof structure, a plurality of roof panels covering said roof structure and providing a plurality of upwardly-inclined air passages, each of said panels comprising upper and lower abutting laminated assemblies, each assembly comprising superposed metal foil layers with a layer of thermal insulating epoxy resin metal-bonding adhesive between adjacent foil layers, the thickness of the adhesive being of the order of about the thickness of the foil layers, a similar adhesive layer between said assemblies and uniting the two assemblies together, the last-mentioned layer of adhesive being interrupted between a pair of spaced-apart parallel lines extending in a direction parallel to the roof inclination, said upper assembly being equipped with an outward deformation between said parallel lines to provide an air passage, said panels being arranged in side-by-side relation with the upper assembly being shorter than the lower assembly in the direction of said lines, whereby said air passages are shorter than the inclined dimension of said roof.

References Cited in the file of this patent UNITED STATES PATENTS 142,641 Mettler Sept. 9, 1873 1,956,323 Gregg Apr. 24, 1934 2,099,598 Carter Nov. 16, 1937 2,229,743 Karcher Jan. 28, 1941 2,318,820 Voigt et al. May 11, 1943 2,423,870 Blessing July 15, 1947 FOREIGN PATENTS 360,244 Great Britain 1931 472,926 Great Britain Oct. 4, 1937 459,897 Canada Sept. 27, 1949 OTHER REFERENCES Paint, Oil and Chemical Review, Nov. 9, 1950, page 15. 

